The autologous grafting of liposuctioned tissue holds much promise in plastic surgery; but being very technique dependent, and lacking a simple apparatus to perform it, it has a reputation for being impractical and unreliable. Generally, as presently performed in the prior art, the process requires harvesting with suction cannulas delicate and finicky adipocytes, separating them, concentrating them, and then re-grafting them a droplet at a time into a three-dimensional recipient matrix in aliquots small enough to survive through diffusion yet separated enough to avoid crowding. The process becomes extremely arduous and time consuming when large volumes are involved. One of the inventors herein has previously invented methods and apparatus for performing fat grafting as shown in pending U.S. patent application Ser. No. 11/409,294, filed Apr. 21, 2006 and entitled Method and System for Preparing Soft Tissue for Grafting, Enhancing Grafting Results, and Grafting Autologous Fat to Soft Tissue Such as the Breast, the disclosure of which is incorporated herein by reference. This process and method represents a significant breakthrough and improvement over the prior art but leaves room for further improvement and refinement. The inventors herein have invented a system comprised of a number of devices each of which is novel but which also function together in a novel way to streamline, simplify and implement fat grafting with a practical procedure having a more predictable success.
The process of liposuction, or the harvest of subcutaneous fat, is commonly performed with a lipoaspirator machine that generates about one atmosphere vacuum pressure and has a collection flask connected in series between the suction cannula and the vacuum pump. It is well accepted that one atmosphere vacuum pressure is most effective if the intent is to simply remove and discard the fat to reduce excesses in body contour. However, if the intent is to reinject this aspirated tissue as a graft, one atmosphere pressure is too high as it inflicts significant damage to the adipocytes sufficient to render them undesirable for reinjection. Therefore, for the purpose of re-grafting or reinjection it is generally known that lower vacuum pressures, closer to one half an atmosphere should be used to yield better fat graft survival. If lower pressures are used however, it reduces the efficiency of liposuction.
The grafting of lipoaspirated fat is increasingly being recognized as a method of restoring volume defects and of improving body contour abnormalities such as may be found in the cheeks, the breast or the buttocks. In addition, tissue carefully harvested by liposuction has been shown to be rich in stem cells capable of regenerating tissue and of improving a number of conditions related to scarring, radiation damage and even aging. Therefore a method and device that would make this process of low pressure harvesting, processing and re-injecting lipoaspirated fat simple, practical and reliable would be of great utility.
The inventors have succeeded in developing such a system that utilizes a number of novel components uniquely suited to low pressure harvesting of lipoaspirated fat. Each of these components themselves have novel and inventive aspects to them, and together comprise a closed system that is uniquely suited to harvesting fat for reinjection.
The inventors closed system includes as its components a very low pressure, multiple opening, cannula for aspirating the fat from the patient; a constant, controlled low pressure syringe mechanism for controllably liposuctioning the aspirate out of the patient with minimal damage to the adipocytes; and a collection bag into which the aspirate is deposited. A multi-port routing valve interconnects these three components with several ports of the routing valve having internal duck bill valves for one way routing of the aspirate both as it is collected and as it is re-injected. Although reference is made throughout this disclosure to a duck bill or flutter valve, it should be understood that those terms apply to any design that opens completely and widely, with minimal pressure gradient, which avoids the slit-like openings of other valve constructions, for example, that force the fat cell suspension to be damaged as it accelerates through the narrow opening. To perform either of the aspiration or re-injection, the syringe mechanism is repeatedly operated to in effect “pump” the fluid through the multi-port routing valve with its one way internal valves. In this way, the aspirate is collected without being exposed to the atmosphere and at low pressures so as to minimize the damage to the delicate and sensitive adipocytes. After collection, the bag is disconnected from the routing valve and one or more bags may be centrifuged at low pressures, such as with a manual centrifuge, to separate the aspirate within each bag into its components of serum, concentrated fat and free oil. After being centrifuged, the supernatant oil is purged from the top of the bag, the serum fluid is purged from the bottom port, and the concentrated fat remains in the bag for re-injection. To perform re-injection, the bag and cannula are connected to the routing valve at each other's ports as used for aspiration. This connection one-way routes the concentrated fat out of bag into the patient by means of the duck bill valve orientation. Then, after the routing valve and cannula are primed, the very low pressure syringe is repeatedly operated to withdraw the concentrated fat from the bag, and then push it through the routing valve and into the patient. Alternatively, instead of the spring syringe system, a small 1-5 ml syringe is preferably used with a simple spring on the plunger which brings it automatically back each time the surgeon's fingers push down on it to empty the grafts into the patient. Throughout this process the aspirate is not exposed to the air, only very low pressures are used to move the aspirate through the system, a low speed centrifuge is used to concentrate the fat from the aspirate which can be collected into multiple bags to speed the concentration process, and the same system components used to collect the aspirate are used to re-inject the concentrated fat. This closed system and method provide significant improvements over the prior art, and will be more fully understood by referring to the drawing figures and description of the preferred embodiment that follows.